That's why I say for the firmware update, make sure you read everything.
And write out the directions if you have to before starting.
edit: All firmware updates have the potential of making your device unusable (usually only when it is interrupted during the install), whether for a motherboard, a Blu-Ray player, etc. It rarely happens, but it is most important to read and understand the directions prior to beginning.

Quote:

System requirements:
You must have an existing installation of the device for which this update is targeted. This update can not be used for initial device installation.

Based on the above from the firmware download page, I would install that 08-2008 driver/software package first, following all directions to set up the printer, then the firmware update.
You may get your printer back just from the HP uninstall and then installing the driver package, but since you're having the issue the firmware is related to, personally, I'd still install it. If you do get your printer back from the driver package, maybe first print the stuff you need right now, and then do the firmware update.

I cannot be held responsible for the things that come out of my mouth.
In the Windows world, most everything folks don't understand is called a virus.